We have not had double glazing fitted by these people, but I have had from them several replacement double glazed panels, including complicated ones with circles taken out, they have always been really helpful and their prices seem exceptionally good. They are Clifton Glass, Builder Street West, Llandudno, LL3 1HH 01492 878905. I would certainly ask them for a quote, steer well clear of the big names like Everest and the like, the advertising they do is reflected in their prices, you cannot beat using a local firm over a national one. Good luck. ££$